Security mechanism for preventing a dead bolt lock being unlocked from outside of the room.
In many places, for example, hotel rooms, there is provided dead bolt locks for purposes of preventing parties from entering the room while the occupant is in the room However usually the door can be unlocked from the outside by a master key which may be used by dishonest employees or other persons.
In No. 4,279,137 to Cook there is disclosed security mechanism that includes a plate having a downwardly opening notch to have the door handle extend therethrough and an elongated notch to have the dead bolt lock handle extend therethrough. Struts are mounted by the plate to prevent the lock handle being turned by one using a key outside of the door when the door handle extends through the notch. Dominguez, No. 3,585,827, functions in a manner somewhat similar to that disclosed by Cook.
In No. 3,263,462 to Suroff et al there is disclosed a locking device that includes a lock having a generally rectangular lock block located inside a room and a lock actuator within the room that is turned when using a key outside of the room. A somewhat U-shaped base has a lower leg to abut against the block lower edge, a second leg adapted to abut against the upper edge of the block, a pair of adjustment screws mounted by the second leg and adapted to be turned for adjusting the spacing of the second leg from the block, and a recess for receiving the lock actuator therein to prevent the lock actuator rotating when it is attempted to unlock the door from outside of the room. One of the limitations of this type apparatus is that if the lock does not have a rectangular block extending into the room the apparatus can not be used in a manner suggested by this patent.
Anderson No. 689,152 disclosed a plate having a curved portion that is inclined at an angle to limit the degree of opening of a door. A screw is threaded into the plate and haS its lower end mounting a foot to abut against the floor. By turning the screw the angle of plate relative to the floor Can be increased above that provided by the curved portion.
In order to provide improvements in devices such as disclosed in the above mentioned patents this invention has been made.